该错误主要发生在两种情况下。首先^(First)是从快照还原来宾虚拟机时，其次是在将附加磁盘连接到系统时存在相同的磁盘标识符时。在这篇文章中，我们将分享如何解决错误The disk is offline 由于管理员设置的策略^{(The disk is offline because of policy set by an administrator)}。

由于管理员设置的策略，磁盘处于脱机状态

您需要管理员权限才能修复此错误。第二个技巧使用Diskpart 工具^{(Diskpart tool)}，使用时应格外小心。如果对您来说太复杂，我强烈建议您与技术人员联系以提供帮助。

1]从快照恢复来宾虚拟机^{(Guest VM)}

使用备份快照还原来宾虚拟机时，还原的来宾操作系统（在虚拟机中）不会自动挂载连接的驱动器。虽然使用实用程序可以看到磁盘，但它们会显示错误消息磁盘^(Disk)已脱机，因为管理员设置了策略。” 它是由于Windows SAN或存储区域网络^{(Storage Area Network)}策略中的问题而发生的。据微软^(Microsoft)称，默认情况下它们被禁用以避免任何数据损坏。以下是如何启用SAN Policy to Online。

san [policy={onlineAll | offlineAll | offlineShared}] [noerr]

在虚拟机中，使用管理员权限打开命令提示符^{(Command Prompt)}或PowerShell 。

使用以下命令启动 diskpart 工具。

C:> diskpart

键入 SAN^{(Type SAN)}以检查策略状态。在我们的场景中它应该是离线共享的。^{(Offline Shared)}

DISKPART> SAN
SAN Policy : Offline Shared

将策略更改为 OnlineAll ：

DISKPART> SAN POLICY=OnlineAll

接下来，当您恢复快照时，磁盘将自动变为联机状态。

相关：^(Related:) 在 Windows 10 中找不到引导设备。

2]磁盘标识符问题

假设您有很多驱动器连接到服务器，并且其中一两个处于脱机状态。磁盘管理^{(Disk Management)}和diskpart 实用程序也无济于事；那么，这是因为相同的磁盘标识符。每个磁盘都有一个唯一标识符。如果它们相同，则其中一个将被停用并显示为脱机并显示警告消息T^(TThe)由于管理员设置的策略，磁盘处于脱机状态。它也称为磁盘签名冲突。^{(Disk Signature Collision.)}

但是，如果您检查日志，您应该识别出一条类似于Disk N has the same disk identifier as one or more disks connected to the system 的^{(Disk N has the same disk identifiers as one or more disks connected to the system)}消息。它是重复磁盘的典型案例。使用Diskpart工具找到它：

从命令提示符打开 diskpart
列出磁盘
选择磁盘 1
唯一标识磁盘

记^(Note)下标识符。检查其他驱动器是否相同。如果存在重复 id 的磁盘，则需要使用Uniqueid 命令更改签名。^{(Uniqueid command.)}

Diskpart 将 UniqueID 设置为磁盘

uniqueid disk [id={<dword> | <GUID>}] [noerr]

要更改签名，请考虑一个唯一编号。
在Diskpart提示符中，键入带括号的 uniqueid disk ID=[NEW SIGNATURE]”
点击^(Hit)回车，它将设置一个新的标识符。通常生成GUID更有意义

uniqueid disk id=baf784e7-6bbd-4cfb-aaac-e86c96e166ee

应用后，计算机应自动识别磁盘。

我希望这两个技巧都能够解决错误。

The disk is offline because of policy set by an administrator

The error occurs majorly in two scenarios. First is when restorіng a guest virtual machine from a snapshot, and second when there are same disk identifiers when сonnecting an additional disk to the system. In this post, we will share how you can resolve the error The disk is offline because of policy set by an administrator.

You will need admin privileges to fix this error. The second tip uses the Diskpart tool, which one should use with extreme caution. I would strongly suggest getting in touch with a technical person to assist if it’s too complicated for you.

1] Restoring Guest VM from a snapshot

When you restore a guest virtual machine using a backup snapshot, the restored guest OS (in the virtual machine) doesn’t automatically mount the attached drives. While the disks are visible using the utilities, they display error message Disk is offline because of the policy set by the administrator.” It occurs because of an issue in the Windows SAN or Storage Area Network policy. According to Microsoft, they are disabled by default to avoid any data corruption. Here is how to enable SAN Policy to Online.

san [policy={onlineAll | offlineAll | offlineShared}] [noerr]

In the virtual machine, open Command Prompt or PowerShell with admin privileges.

Launch the diskpart tool by using the following command.

C:> diskpart

Type SAN to check the policy status. It should be Offline Shared in our scenario.

DISKPART> SAN
SAN Policy : Offline Shared

Change the policy to OnlineAll:

DISKPART> SAN POLICY=OnlineAll

Next, when you restore the snapshot, the disk will automatically become online.

Related: Boot Device Not Found in Windows 10.

2] Disk Identifier Issue

Assuming you have a lot of drives connected to the server, and one or two of them are offline. The Disk Management and diskpart utility also fail to help; then, it is because of the same disk identifiers. Each disk has a unique identifier. If they are the same, then one of them will be deactivated and will appear as offline with warning message TThe disk is offline because of policy set by an administrator. It is also called the Disk Signature Collision.

However, if you check the logs, you should identify a message similar to Disk N has the same disk identifiers as one or more disks connected to the system. It is a typical case of duplicate disks. Use the Diskpart tool to find it:

Open diskpart from the command prompt
List disk
Select disk 1
Uniqueid disk

Note down the identifier. Check if they are the same for other drives. If there is a disk with duplicate id, then you need to change the signature using Uniqueid command.

Diskpart Set UniqueID to Disks

uniqueid disk [id={<dword> | <GUID>}] [noerr]

To change the signature, think of a unique number.
In the Diskpart prompt, type uniqueid disk ID=[NEW SIGNATURE]” with the brackets
Hit enter, and it will set a new identifier. Usually generating a GUID makes more sense

uniqueid disk id=baf784e7-6bbd-4cfb-aaac-e86c96e166ee

Once it is applied, the computer should automatically identify the disk.

I hope both of these tips were able to resolve the error.

鑫赵

About the author

我是一名软件工程师，拥有 Xbox Explorer、Microsoft Excel 和 Windows 8.1 Explorer 方面的经验。业余时间，我喜欢玩电子游戏和看电视。我拥有犹他大学的学位，目前在一家国际公司担任软件工程师。

由于管理员设置的策略，磁盘处于脱机状态

由于管理员设置的策略，磁盘处于脱机状态

1]从快照恢复来宾虚拟机^{(Guest VM)}

2]磁盘标识符问题

The disk is offline because of policy set by an administrator